Tanks

After a long war with savage monsters, humanity is decimated. Many areas are poisoned, so is the city from which the main characters come from. They have been sent out to get a new water purifier for the city, as the old one is starting to wear out, a journey that will take them through distant and dangerous countries. To their aid, however, they have two minitanks, humanity's foremost mobile weapon. It does not take long before things start to pile up, and the small group soon gets a lot to think about.